Automatic telephone system



April 10, 1926. j 1,665,466

D. R. MIDDLETON AUTOMATIC TELEPHONE SYSTEM Filed Aug. 24. 1923 Patented Apr. 10, 1928.

N1 TED STATES Pn Tam DONALD R. MIDDLETON, OF DETROIT, llIIGI-IIGAN, ASSIGNOB,BY MESNEASSIGNMENTS,

TO AUTOMATIC ELECTRIC INC., 'OF CHICAGO, ILLINOIS, A CORPORATIONOF DELA- WAR-E.

AUTOMATIC TELEPHONE SYSTEM.

Application filed August 24, 1923. Serial 'No. 659,066.

This invention relates in general "to automatic telephone systems and its object, broadly stated, is to provide a newand improved common talking selective signalling 5 system. More specifically, the object of the invention is to provide an inexpensive system for private installations, comprising a common talking line with a plurality substations thereon, together with a connector switch to furnish individual or selective signalling.

To accomplish the foregoing and other useful ends this invention comprises means which will be fully described in the specification which is to follow, reference being had to the accompanying drawing, which shows diagrammatically the apparatus and circuits involved in a system embodying the invention.

The substation A, A and A are all connected in bridge of a single pair of talking conductors and may be of any approved automatic type. As shown at A, they comprise essentially the receiver 1, switch-hook 2, transmitter 3, calling device 4, and buz zer 5.

The common line conductor 11, of the substations, is grounded at the connector H, while the common line conductor 12 is connected to the line relay of the connector, which is mechanically of the well-known vertical and. rotary type of switch and has its bank contacts arranged in horizontal rows or levels. All the contacts in the upper bank of the connector, the contacts adapted to be engaged by wiper 58, are grounded,

while the contacts of the lower bank, associated with wiper 59, are connected to the individual signalling conductors such as 13 extending to the several substations, such as A Associated with the connector is a control mechanism S, consisting essentially of the solenoid 6'6, which pulls the plunger 61 up when current flows through the former. In order to secure the proper slowness of operation of the plunger the dash-pot 62 is as sociated with the lower end thereof. This dash-pot may be of any well known design.

Having given a brief descriptionpf the apparatus, the operation of same will now be explained more in detail. For th1s purpose, it will be assumed that the subsorlber lat'station A'desires-to call the subscriber "at station A 011' the" common talking line. In

order to dothis, the subscriber at station A removes'his receiver and then dials the number of station A v When the'receiver is removed at substation A, line relay '31energiz'es'over *a cuit from, ground, line conductor 11, switchhook 2 and its workingfcontact, receiver 1,

'- transmitter 3, calling device 4, line conductor 12, relay 31, to grounded battery. Upon energizing, line relay 31 clo'sesa circuitat armature 51 for "slow acting rleaserelayea Release relay 32, upon 'energizing,'prepares a circuit for the vertical magnet 37 at its armature 52.

The calling subscriber A "mayf'novv proceed to operate his calling device in accord- .ance with the "first digit 'in the -desired number, which in this case is '1. As a result one interruption is produced in the clircuit of the lin'e'relay 3-1. In response tothe single deenergiz'ation of line relay 31, an impulse of current is sent to vertical magnet 37 over the following circuit: from ground by way of armature 51 and its resting contact, armature 52 and its working contact, resting contact of as normal spring 40 and said spring, slow acting series relay 33, and vertical magnet 37 to groiinded battery. Series relay 33, upon er'ierg'iiiiug,

opens the circuit to the rotary magnet 38 at armature "54; and closes a second circuit for itself and vertical magnet '37 at armature 53 for use after the off normal 's'prings have shifted, as they do upon the first vertical step. By the operation of vertical magnet 37, the switch wipers 58 and 59fare raised opposite the first level of bank contacts At the end of the vertical movement, relay 3'3 deenergiz es and transfers the 6pe'rating circuit from the vertical to the rotary magnet. V

The calling ubscriber may Row -pane his calling device in accordance with the second digit in the desired number, which in this case is 3. As a result three interruptions are produced in the circuit of the line relay 31. In response to each of the resulting deenergi'za'tions of line relay3l, an impulse of current is sent to rotary magnet 38 over the following circuiti from ground by way of armature 51 and its resting contact, armature 52 and its working contact, normally open contacts controlled by oil normal spring40, armature 154 and its resting contact, slow acting relay 34, and rotary magnet 38 to grounded battery. By the operation of rotary magnet 38, the wipers 58 and 59 are rotated step by step into ongagement with the contacts 71 and 72, re-j spectively, the former being grounded and thelatter being connected with thesignaling conductor of the called substation. Relay 3%, upon energizing, opens the circuit of relay at armature 55 and, being slow acting,

retains its armature attracted throughout the rotary movement, thus preventlng relay 35 from energizing during rotation.

At the end of the rotary movement, relay 34 deenergizes and. closes a circuit for relay 35 at armature 55 as follows: from ground seconds. Spring 65, uponbeing operated by way of contact 71, wiper 58, relay 35, armature 55 and its resting contact, ofl normal spring 39 and its working contact, and

release magnet 36 to grounded battery.

Magnet. 36 will not energize in series with relay 35 due to the high resistance of the latter. Relay 35,.upon energizing, closes the signalling circuit for the called station A at armature 57 and closes the circuit to the solenoid ,66 of the control mechanism S at armature 56. Buzzer 25 .is actuated over the signalling circuit as follows: from grounded battery by way of resistance 60,

working contact at armature 57 and said. armature, w1per'59, contact 72, signalllng .GlICIlltS relay 35. Relay35, upon deener-.

gizing, opens the si nalling circuit at armature 57 and stops t e buzzer 25 from operating; and opens the circuit for solenoid 66 at armature 56. Release magnet 36, upon energizing, restores the wipers58 and'59 to normal; position, and its circuit is opened at off normal spring 39 by the switch shaft when the wipersreach their normal position. Solenoid 66, upon deenergizing, permits the plunger 61 to drop back to normal,

which in turn to normal. e

When the subscriber at station A? re permits spring 65 to return sponds to the actuation of his buzzer. by

removing his receiver, his telephone is connected across the common talkmg ;llI18,

whereby he and the calling subscriber A may now converse with each other asdesired.

If the subscriber at station A does not use again.

respond to the first actuation of his buzzer the subscriber at station A may actuate it a second time, or as many times as he dosires, by redialling the number, with his ergizes. The connector H isnow in normal positionand the common line is ready for The principal advantage in a system simis lar to the foregoing lies in the factthat a large number ofsubscribers, within limited distances andhaving a very lowcalling rate,

can have inter-communicating telephone service very cheap and still have individual signalling. The system is inexpensive since only one of the large type switches, a connector, is used and stations can be added or rearranged without the customary wiring rearrangements in a multiple system,

. Having described my invention, what I consider to be new and desire to have protected by Letters Patent will be pointed out -in the appended claims.

What I claim is: I

1. In a telephone systeni,racommon talking line provided with a plurality of subscribers stations, a plurality of individual signalling conductors, an automatic switch, means controlled from. one of said stations foroperating said switchto connect to any one of said conductors, automatic signalling equipment in said switch, and

means operative responsive to the establishe ment of said connection forconnecting said signalling equipment o apply signalling current to said conductor for a pro-deterinined interval to. signal a station onsaid me. i i i i 2. In a telephone system, the combination with a common talk ng line provided with a plurality of subscribers ,stations, of. an automatic switch, a plurality of individual signalling conductors extending to said sta- I I tions, respectively, and automatic means controlled over said lines for connecting said sWitch to any one of said signalling conductors to signal the. station individual to that conductor. y V 1 v 3. In a telephone system, a common talking line having a plurality of subscribers stations thereon, and selective signalling apparatus common to said stations for enabling one subscriber on said line to call another, said signalling apparatuscompris ing means for transmitting signalling current from the selective signallin'g'apparatus to the called subscribers station over a'oonductor separate from said line and individual to the called station.

4. In an automatic telephone system, a common talking line, a plurality of subscribers stations, a signalling terminal and conductor and a grounded terminal for each of said stations, signalling apparatus for enabling one subscriber to signal another, said apparatus comprising means operated over said grounded terminals for signalling the stations on said line by projecting signalling current over said signalling terminals and conductors individual to the stations, and also comprising means for stopping the signalling operation after a pre-determined interval.

5. In a telephone system, an automatic switch, a signalling conductor, means for operating said switch to connect to said conductor, means in said switch for applying signalling current to said conductor for a predetermined interval, and means for automatically releasing said switch at the termination of said interval.

6. In a telephone system, a called substation, a pair of talking conductors and a sig nailing conductor for said substation, an automatic switch, means for operating said switch to connect to said signaling conductor, means in said switch for applying signalling current to said conductor, and means for disabling said second means at the termination of a predetermined interval.

7. In a telephone system, a line terminating at a common switching point, a plurality of subscribers stations on said line, individual signalling conductors extending from said common switching point to said stations, respectively, and a signalling circuit for each of said stations including one of the conductors of said line and the individual signalling conductor of the station in series.

8. In a telephone system, a common talking line having a plurality of substations thereon, a battery for supplying talking current, one conductor of said line being con-- nected directly to one side of said battery and the other conductor of said line being connected through an impedance to the other side of said battery, individual signalling conductors extending to said substations, respectively, and a signalling circuit for each of said substations including the said first conductor, the individual signalling conductor of the substation, and said battery in series.

9. In combination with a plurality of telephone stations having common talking and individual ringing conductors, a connector, means for operating the connector over a common talking conductor to select a desired ringing conductor, and time delayed means effective when the connector has been operated and independent of control over a talking conductor, for releasing the connector.

10. In a telephone system the combination with a plurality of stations on a party line, of a connector, individual conductors extending from each station to the connector, means for operating the connector to select any of said conductors and project ringing current thereover, and means efiective a predetermined period of time after the operation of the connector for releasing the same and cutting off the ringing current.

In witness whereof, I hereunto subscribe my name this 16th day of August, A. D. 1923.

DONALD R. MIDDLETON. 

